Hydraulic elevator torque damper



June 29, 1937. E.. Q ROSENEBRG 2,085,230

HYDRAULIC ELEVATOR TORQUE DAMPE'R Filed Sept.. 17, 1952 Snventor Mlmmw aienied `une 29, i937 UNITE@ Swii @ATENT GFFEC 3 Claims.

My invention relates to improvements in hydraulic elevator torque damper.

The object of my invention is to provide means whereby a hydraulic elevator operated by a motor 5 driven pump may be stabilized in its operation, may be so constructed as to prevent jarring, and unduly rapid starting and stopping in its upward movements.

More specifically stated, it is the object of my invention to dampen out the starting and stopping acceleration and deceleration of a hydraulic elevator by providing a heavy fly wheel upon the motor shaft, and to so construct that fly wheel that the cutting off of a portion of the flange thereof may be accomplished at the factory upon mathematically figured data, including the weight of the cage and the estimated load requirements to adjust the dampening effect in accordance with the demands of the particular installation.

In the drawing:

Figure 1 is a side elevation of a hydraulic elevator structure embodying my invention, a portion of the main cylinder being shown in Vertical section.

Figure 2 is a vertical section through the fly wheel shown in Figure 1.

Figure 3 is a section showing the fly wheel adjusted for lighter loads.

Like parts are identified by the same reference characters throughout the several views.

In a hydraulic elevator the cage IIJ, shown in fragmentary view in Figure 1, is mounted upon a ram which operates in a cylinder I2. A piston I3 on the end of the rarn is caused t0 be elevated in the piston I2 by fluid pressure in the space I4 below the piston. Pressure of the i fluid at I4 is controlled by means of a pump I5 which passes fluid from a reservoir I5 through pipe and into pipe I8, leading into the 40 cylinder.

Pump I5 is of the gear or vane type, the operating element of which is housed in the main pump structure I5 and is actuated by a shaft i9 coupled to the armature shaft 2G of a motor 2 I.

Structure of the type thus far described is common in the hydraulically operated elevators heretofore known. Each of such elevators is, of course, installed in locations calling for certain maximum and minimum load requirements,

and the sizes of the parts used in general correspond to the size of the loads expected to be carried. However, it is obvious that loads carried by elevators will vary from time to time, and in any event, a wide range of load capacity may be expected.

If the load in cage I0 is light the energizing of motor 2|, which has a capacity for an exceedingly heavy load in cage I0, causes an exceedingly rapid passage of fluid through the pump I5 and through the pipe I8 into the cyl- 5 inder so as to rapidly accelerate the movement of the cage l in an upward direction. Assuming a heavy load in cage I0, the motor 2| undertakes its burden of forcing the pump I5 to thrust liquid into the chamber I4 beneath the piston 10 slowly and gradually so that the load starts easily and satisfactorily.

However, when the cage approaches a higher level comprising its unloading point, the deenergization of the motor 2| is the signal for 15 instantaneous stoppage of the elevator, since the heavy load and its resistance to further flow of liquid in pipe I3 will induce a considerable back pressure to stop the rotation of shaft I9, and therefore of armature shaft 20. o

On the other hand, the light load which was started with unnecessarily rapid acceleration from the lower level approaches the upper level or unloading point at a maximum speed, and the deenergization of motor 2| does not immediately result in stoppage of the elevator since the armature shaft 20 and the shaft I9 of the pump will tend to continue in rotation with the result that the cage ID may pass the unloading point and necessitate a readjustment by the operator of 30 the controls so as to return the elevator downwardly to its proper unloading point.

To avoid these difficulties I provide upon the end 22 of the armature shaft a fly wheel 25 which comprises a hub 26, a web 2l, and an elongated annular flange 28, This y wheel, situated as it is upon a shaft '22, integral with shaft 2t and secured to the pump through shaft I9, has an advantage with reference to the fluid pressures at Ill by reason of the inherent 40 capacity of the pump I5. With a fly wheel 25 of the proper weight adjusted to the capacity of the elevator cage IG, I am able to control the starting of a light load, since the motor 2| must overcome the inertia of y wheel 25 as well as 45 the inertia and weight of the load in the cage IQ.

The inertia of fly Wheel 25 must, of course, be overcome when the load in cage I!! is great, but the diiculty in starting a large load in cage it, even though augmented by the inertia of the fly 50 wheel 25, is not an objectionable feature in the operation of a hydraulic elevator, and when the heavy load in cage ID approaches the unloading point at a higher level the deenergization of the motor 2| is not asignal for sudden stoppage, since 55 the fly wheel 25 has the momentum of stored inertia which in being overcome accomplishes work in raising the elevator to the higher level. The heavy load on cage il) does not, therefore, immediately stop with a jolt.

If the elevator has a light load in cage Nl and the fly wheel with its inertia must be slowly started, it will likewise slowly stop at the higher level without the diiierence in operating effect which would otherwise be the case if the ily wheel Was not there.

The result of operation of the hydraulic elevator with my fly wheel is smooth starting and smooth stopping, something that has been sought in elevators of this type throughout the history of hydraulic elevators.

Obviously, a single y Wheel would not be suitable ior all types of installations in conjunction with all sizes of hydraulic elevators. I have found, however, that a single fly wheel may be provided With an elongated annular ange 28, and a portion of the annular flange as delineated in dotted lines at 29 in Figure 2 may be cut away at the factory from a stock Wheel. Adjustments may thereby be madeV for large or small installations by cutting OIT the excess of flange 25.

I claim:

1. The combination with a hydraulic elevator including a cylinder, a ram, and a positive displacement pump with appropriate direct pipe connections for establishing unyielding liquid pressure in the cylinder, of a shaft for operating the pump, a substantially constant torque motor attached to the pump shaft, and a torque damper comprising a ywheel upon said shaft.

2. The combination with a hydraulic elevator including a positive displacement pump therefor adapted to start and stop in accord with elevator movement, a shaft for the pump, a substantially constant torque motor coupled to said shaft, and a fly wheel for said motor provided with an elongated flange weight adapted to be initially and permanently adjusted in accord with the capacity of the elevator.

3. The combination with a hydraulic elevator and a pump there-for adapted to start and stop in accord with elevator movement, of a motor coupled to the pump whereby to provide a liquid supply to the elevator substantially without pulsation, and a heavy fly-wheel connected to the motor, whereby to damp starting torque and resist deceleration thereof.

EDWIN C. ROSENBERG. 

